Methods Highly oxygenated blood was perfused into carotid arteries of 22 patients with severe head injure at about 3.

Clinical investigation of non-invasive positive pressure ventilation in treatment for patients with chronic obstructive pulmonary disease and severe respiratory failure complicated with hypercapnia;

Results The simulation experiments show that cardiac sympathetic activities,cardiac oxygen consumption and myocardiac contractility increased during hypercapnia hypoxia.

The research on effect of sildenafil on human physiological functions at high altitude and its use in prevention and treatment of high altitude pulmonary hypertension,high altitude pulmonary edema and high altitude hypoxemia,and improving motor ability are reviewed.